Performance comparison of a photosynthetic and mechanically aerated microbial fuel cell for wastewater treatment and bioenergy generation using different anolytes

Abstract

The use of expensive catalyst or mechanical aeration to carry out reduction reaction at cathode of conventional microbial fuel cell makes it costly and less efficient. Photosynthetic microbial fuel cell (PMFC) provides an option to overcome these issues by using microalgae as a biocatalyst at cathode chamber. This study aimed at assessing the performance of photosynthetic microbial fuel cell (PMFC) and its comparison with mechanically aerated MFC (MAMFC). The performance of both the systems was evaluated for two different anolytes namely, domestic wastewater and sugar industry wastewater. The PMFCs were inoculated with biocatalyst of Scenedesmus sp. in cathode chamber. Results showed that photosynthetic aeration significantly improved the efficiency of PMFCs as compared to MAMFCs. Maximum working voltage of 316 and 515 mV was achieved by PMFC with domestic wastewater and sugar wastewater, respectively, which was 15 % and 20 % higher than corresponding voltage of MAMFCs. Polarization and power curves showed that higher power density and lower internal resistance was achieved in PMFCs as compared to MAMFCs with both anolytes. Effect of light/dark regime on PMFCs resulted in a rise and drop pattern of dissolve oxygen and voltage generation. During light cycle, the average voltage was 214 mV and 370 mV for PMFC with domestic wastewater and sugar wastewater, respectively, which was 55 % and 54 % higher than corresponding dark cycle. Overall, the findings of the study suggested that PMFC support better power generation as compared to MAMFC, besides nutrients removal and production of algal biomass.